Raw material combined with color masterbatch is first mixed, then fed under vacuum, dried, and processed through a single-screw extruder and a color line extruder. The material is then shaped using a spiral mold, followed by sizing sleeves, spray vacuum setting boxes, and cooling in water tanks. After that, an inkjet printer marks the product, which is then transported by a crawler tractor for final inspection and packaging. This process results in PPR pipes of specific dimensions. PPR pipe specifications are defined by the series S, nominal outer diameter (dn), and nominal wall thickness (en). For example, a PPR pipe with series S5, a nominal outer diameter of 25mm, and a wall thickness of 2.5mm would be represented as S5, dn25×en2.5mm. The series S is a dimensionless number used to classify PPR pipes. It is calculated using the formula S = (dn - en) / (2 × en), where dn is the nominal outer diameter in millimeters and en is the nominal wall thickness in millimeters. Commonly used series include S5, S4, S3.2, S2.5, and S2. PPR pipes are also categorized based on the Standard Dimension Ratio (SDR), which is the ratio of the nominal outer diameter (dn) to the wall thickness (en). The relationship between SDR and the series S is given by SDR = 2S + 1. This helps in determining the pressure rating and application suitability of the pipe. PPR pipe fittings are specified based on the nominal outer diameter (dn) of the connected PPR pipe. The wall thickness of the fitting should not be less than that of the corresponding pipe in the same series. Most companies produce fittings for the highest standard, S2 series, suitable for both hot and cold water applications. Pressure ratings for different series are as follows: Industrial production of PPR pipes involves several methods. Traditionally, hydrocarbon slurry or suspension processes were used, where an inert diluent helped control the reaction. However, this method is now outdated. Bulk or high-pulp processes use liquid propylene as a medium, while gas-phase processes involve gaseous propylene and a solid catalyst in a fluidized bed reactor. These modern techniques allow for greater flexibility and efficiency in manufacturing. 2835 Led Chip,2835 Lamp Led Chip,2835 Smd Led Chip,2835 Led Light Module Shenzhen Huangtai Photoelectric Co.,Ltd. , https://www.huangtailed.com